Biophysics and medical physics

Optical Clearing as Method to Increase the Depth of Nanoparticles Detection in the Skin with OCT-Visualization

Background and Objectives: Nanoparticles of titanium dioxide are now widely used both for the creation of sunscreen filters, and as carriers of drugs. One of the ways of transepidermal delivery of these nanoparticles to the dermis of the skin is their penetration into the hair follicles. However, optical control of the filling of follicles with nanoparticles is rather difficult due to strong light scattering in the skin.

Prospects For Application of Upconversion Particles NaYF4:Er,Yb for Phototherapy

Background and Objectives: Functionalized upconversion particles allow for photodynamic and photothermal therapy of tumor with simultaneous temperature monitoring and visualization of the area of treatment. Upconversion particles can increase the depth of therapeutic effects due to the high penetration depth of the required excitation radiation. That is why they are a promising material for the combined phototherapy and simultaneous monitoring of biological tissue heating.

Acoustoelectronic System for High Intensity Focused Ultrasonic Radiation Forming Aiming Nano- and Microsized Containers Opening

Background and Objectives: The aim of the study is to develop a system intended to the controlled release of preparations that were encapsulated to micro- and nanochambers. The system also allows to implement the optoacoustical diagnostics of the object by means of short light pulse radiation with the successive processing of the appeared ultrasonic signal. Short description: The system consists of two parts: electronic and acoustical ones. The electronic part represents a radiofrequency generator of electromagnetic radiation.

Mathematical Model of Vascular Tone Autoregulation

Background and Objectives: The conventional approach to study the blood circulat ion in the cardiovascular system of humans and animals is based on representation of the vascular system as a hierarchical structure of branching elastic tubes. While considerable progress has been achieved in the framework of this p aradigm, the other fails when one needs to analyze the dynamical patterns in networks of small arterial vessels.

Study of Statistical Characteristics of GB-speckles, Forming at Scattering of Light on Virtual Structures of Nucleotide Gene Sequences of Enterobacteria

Background and Objectives: A brief review of methods of modern bioinformatics, based on the usage of virtual optical GBspeckles (gene-based speckles), has been presented in this paper. An algorithm of transformation of a nucleotide sequence into a 2D GB-speckle-structure has been proposed and discussed.

Estimation of Glucose Diffusion Coefficient in Human Dura Mater

Background and Objectives: Optical clearing of dura mater caused by hyperosmotic immersion liquids is important for the development of noninvasive methods of brain optical tomography and for the study of microcirculation and homeostasis of tissue fluids. It allows significantly increasing the spatial resolution and the probing depth of brain. Obviously, a quantitative description of the optical clearing processes requires the development of reliable physicomathematical models, which in turn requires the knowledge of the diffusion rate parameters of immersion agents in tissues.

Optical Doppler Methods for the Measurements of Flow Velocities of Biological Liquids

Background and Objectives: In this paper the key results obtained by the authors during the years of development of Doppler optical methods for quasi-elastic light scattering and coherence gating on biomedical liquids are presented. The research is focused on the sign sensitive velocity measurement and quantitative visualization of alternating and complex geometry flows using spectral approach to digital data processing of Doppler shift of the carrier frequency.

HETEROPHASE SEMICONDUCTORS UNDERACTION OF IRRADIATIONS

The history and current state of our heteropfiase photoconducting CdS-PbS films investigations are observed. Films were prepared by the vacuum evaporation method from the materials with limited mu tual solubility. Reasons of increased degradation stability with respect to radiation (in particular y- and electronic irradiations) are found out. Degradation stability is explained by diversion of recombination flow from wide-gap phase to narrow-gap. Radiation stimulated defects also move to narrow-gap phase.

НЕСТАЦИОНАРНОЕ ВОЗБУЖДЕНИЕ ОТКРЫТЫХ СТРУКТУР

Получены нестационарные электродинамические уравнения возбуждения открытых резонаторов и волноводных трансформаторов, основанные на методе функций Грина. Для открытого резонатора получены также аналогичные формулы, основанные на спектральном подходе. В общем виде задача о возбуждении сводится к интегральным уравнениям в пространственновременной области.

ГЕНЕРАТОР АНИЩЕНКО-АСТАХОВА КАК ОДНА ИЗ БАЗОВЫХ МОДЕЛЕЙ ДЕТЕРМИНИРОВАННОГО ХАОСА

В обзоре формулируются условия возникновения хаотических автоколебаний и дается радиотехническая схема генератора, которая эти условия реализует. Выводятся уравнения генератора Анищенко-Астахова и проводится их анализ. Особое внимание уделяется взаимосвязи уравнений генератора с классическими моделями Теодорчика и Ван дер Поля.

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